Effects of chenodeoxy- and ursodeoxycholic acid on absorption, secretion and permeability in rat colon and small intestine.

The effect of equimolar concentrations of chenodeoxycholic (CDCA) and ursodeoxycholic acid (UDCA) on the colonic absorption of water, sodium and oxalate, and on the transmural potential difference was examined in the rat colon by an open perfusion technique. In addition, the ileal absorption of D-glucose, oxalate, water and sodium was measured in the presence and absence of CDCA and UDCA. CDCA reversed the absorption of water and sodium into secretion more effectively than UDCA Oxalate absorption and permeability of the colon measured by the disappearance of D-mannitol were enhanced by CDCA, but to a lesser extent by UDCA. The ileal absorption of water and sodium was nearly abolished by CDCA and inhibited to a lesser extent by UDCA in the presence of D-glucose in the perfusate. At equimolar concentrations, CDCA induced a more marked inhibitory effect on colonic function than UDCA. This quantitative difference may account for the less frequent side-effects of diarrhoea in cholelitholytic treatment with UDCA compared to CDCA.